Flanges attached to the wave guide ends are usually used in coupling two wave guides to each other. The wave guides are finally coupled together by connecting the flanges, using a bolted connection. A problem here is how the flange in its turn is to be fastened to the wave guide.
A known method of attaching a flange to a wave guide is by brazing when the flange is made from brass or by dip brazing when it is made from aluminium. These methods are expensive, however.
It is already known to mechanically attach the flange to the wave guide, for example, the GB-B No. 1.025.928 teaches an attachment where the flange is provided with a muff which can glide along the outer wall of the wave guide when it is applied. For attachment, the flange is adjusted so that the grooves in the muff are directly opposite depressions in the wave guide wall. Rectangular pins are then pressed in, which are firmly wedged in the muff of the flange as well as in the depressions, thus fixing the flange to the wave guide wall.
Another method of mechanically attaching a flange to a wave guide is illustrated in GB-B No. 1.302.133. Here the flange has a rectangular opening part with a bore in each corner thereon. After the flange has been fitted to the wave guide, hollow screws are driven into the bores and then pins are driven into the screws, which expand and lock the flange to the wave guide.